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Home , Dickcissel, Eastern meadowlark, Indigo bunting, Passerina

THE NESTING BIOLOGY OF THE (SPIZA .AMERICANA) IN NORTH CENTRAL OKLAHOMA

By GORDON ALAN Bachelor of Education Keene State College Keene, New Hampshire 1961

\

Submitted to the Faculty of the Graduate College of the Oklahoma State University in partial fulfillment of the requirements for the Degree of MASTER OF SCIENCE July, 1971 OKLAHOMA STATE UNIVERSITY

THE NESTING BIOLOGY OF THE DICKCISSEL (SPIZA AMERICANA) IN NORTH CENTRAL OKLAHOMA

Report Approved:

/ean of the Gij>date College

ii ACKNOWLEDGMENTS

I wish to express sincere appreciation to Dr. John S. Barclay who served as major adviser on this report; to Dr. James K. McPherson for assistance in plant identification; to Dr. L. Herbert Bruneau, the Director of the Academic Year Institute at Oklahoma State University and also· ·major advisor during the past school year; and to the National Science Foundation for providing the financial assistance and oppor­ tunity to participate in the master's program. Thanks are given to Mr. and Mrs. Ivan Lurz for helpful suggestions offered and for photographs taken, and to Mrs. Ann Smith who typed the report. Finally, I would like to express appreciation to my wife, Patricia, for her assistance and encouragement during preparation of this report.

iii TABLE OF CONTENTS

Chapter Page

I. INTRODUCTION • • • ...... 1 II. THE: STUDY TRACTS • ...... 3

General Description • • • • • • • • . . • • 3 Vegetation of the Study Tracts ...... • 9 III. MATERIALS AND METIDDS ...... • 13 IV. NESTS ...... • 15 Nest Construction ...... • 16 v. CLUTCH COMPLETION ...... • 19 VI. ADULT PREFLEDGING ACTIVITY ...... • 21 VII. CONCLUSIONS ...... • 25 LITERA.TURE CITED ...... • 27

iv LIST OF TABLES

Table Page

I. Comparison of Physical Characteristics of the Study Tracts • • • • • • • • • ...... 8 II. Commonly Occurring Plant Found on Tract I • • • • • • • • • • • • • ...... 9 III. · Commonly Occurring Plant Species Found on Tract II • • • • • • • • • • • • ...... 10 IV. Observed on the Study Tracts • • • • • • • • 11 V. Dimensions of 6 Dickcissel Nests Found on Study Tracts • • • • • • • • • • • ...... 17 VI. Number, Date Found, Status and Location of 6 Dickcissel Nests Found on Study Tracts • • • • • • • • 17

VII. Typical Feeding Time Table of Dickcissel • • • • • • 22 VIII. Hatching and Fledging Success of 6 Dickcissel Nests ••••••• ...... 24

LIST OF FIGURES

Figure Page

1. Typical view of Tract I •• • • • • ...... 4

2. Typical view of Tract II . . . . • . • • • . • . . . . . • . 5

3. Map of Tract I . • ...... • . . • • . . . . 6

4. Map of Tract II . • ...... • . . . . • . • . 7 5. Nest 3 with Completed Clutch . . . . 20 6. Nest at Tract I with First Nestling ...... 23

v CHAPTER I

INTRODUCTION

The Dickcissel (Spiza americana) is a midwestern, . It is 6 to 7 inches in length. The upper parts are streaked with gray, brown and black with the lower parts white and yellow. Its bill is stout, conical, and laterally compressed. The wings are long and pointed. The tail is about 3/4 the length of the wings and is forked.

The Dickcissel is about the size of a House Sparrow ( domesticus domisticus) and has similar markings, sometimes causing experienced birdwatchers to confuse the two species.

The nesting range of the Dickcissel is limited chiefly to the region of the middle west between the Alleghenies and the Rocky

Mountains, and from Michigan, Wisconsin, Minnesota, and North Dakota south to Alabama, Mississippi, Louisiana, and (Peterson, 1947).

The species winters in .

In addition to being an interesting small bird of our , the Dickcissel may have an important economic status. Gross (1921) estimated that the Illinois saved the State about $4,680 daily during the nesting season by the destruction of , in addition to consuming other harmful and the of weeds.

There have been 2 major studies conducted on the Dickcissel in

Oklahoma. The first of these was conducted by Edward Crabb in 1923

1 2 on the nesting activities of a pair of Dickcissels near Yukon, Okla­ homa. His study included observations on nest construction, egg laying, incubation, and care of the prefledglings. The second and most extensive study was conducted by Thomas Overmire during the spring and summer of 1960 and the summer of 1961. His study was con­ cerned with the effects of grazing upon the utilization of the

Dickcissel and Bell's Vireo (Vireo bellii) in Payne County. He found that grazing did not reduce the nesting success of either species.

However, the population densities of both species were approximately

50 per cent less on grazed land.

Other than these two studies, there is little available published literature on the nesting biology of the Dickcissel in Oklahoma.

Therefore, the lack of scholarly research in this area indicates a need for field research. The purpose of this paper, then, is to present data collected from 17 May to 13 June 1971 and to draw con­ clusions based on field research and information gathered from previous studies. The objectives of this report are: to supplement existing information on life history and resultant Dickcissel popu­ lations; to compare established and disturbed natural in north central Oklahoma; to survey literature, to determine the extent of information on the Dickcissel; to develop expertise in field research. CHAPTER II

THE STUDY TRACTS

General Description

Two tracts were utilized in this study. Both tracts were near

Stillwater, Oklahoma, and together comprised an area of 68 acres.

These two particular tracts were selected because of their habitat

and accessible nature. The particular habitat of these areas seemed

especially promising since the vegetation and physiographic features were similar to that of the study conducted by Overmire. The readily

accessible nature of the tracts made more observation periods

possible. The selection of two tracts, with differing physiographies

and differing stages of succession (to be discussed later in this

chapter) enabled this study to be comparative in nature.

Tract I was located on one of the Oklahoma State University farms,

one mile west of Stillwater, near the corner of McElroy and Western

Avenue. The farm was acquired by the University in 1952 and has been

used for grazing. Figure 1 shows a typical view of Tract I. The

exact location of this tract is section 9, T. 19N., R. 2E., Indian

Meridian, Payne County, Oklahoma.

Tract II was located slightly northeast of the base of the dam

at the Lake McMurtry Project in Noble County on land owned by the City

of Stillwater. The land had been cleared and leveled in order to

prepare a bed for the new impoundment. Figure 2 shows a typical view

3 4 of Tract II. The exact location of this tract is section 35, T. 19N .,

R. lE., Indian Meridian, Noble County, Oklahoma.

Figure 1. Typical Dickcissel nesting habitat on Tract I, looking east.

A direct comparison of Tract I and Tract II indicates the following differences in land treatment: first , Tract I was grazed land~as was evidenced by numerous cow chips in the area~whereas

Tract II exhibited no evidence of recent grazing activities. Instead,

Tract II showed signs of frequent human activity and disturbance indicative of recently bulldozed land. Secondly, Tract I appeared to

contain relatively undisturbed native grassland vegetation whereas

Tract II appeared to be in an early successional stage, probably due to the recent scraping and bulldozing activities in construction of the McMurtry Dam . The implications of this disturbance in terms of

Dickcissel population are slight and largely conjectural on the basis of the observations made in this study. Specific data which characterize the tracts are given in Table I . Maps of study tracts

I and II are shown in Figures 3 and 4 respectively.

Figure 2. Typical Dickcissel nesting habitat on Tract II, looking east. 6

~~~--,-~~~~1u1~~--,r-~~.N

11 II I '

I CJ . /. *l I fJ --- )/ /'~ // / I. 11 / f I I I I II I . #'II I I » I I I Rye Field I I I \I I I &J~@ \ 8! \ . ! '\. I II ·I ------It Nest . /( * I ~ Trees Grass I \ ® Pond . ~ Pecan Grove J 011 ·-·-·- Fence j ==-== ==Dirt and Grass Roa

p

W.McElroy

Figure 3. Map of Tract I Scale: 1 11 = 250' = 1 grid 7

N..... ~--- r·-·-··-· . -·-. -·-. ~ ·-~ . - ·-·-·-.

Drainage Dam ... Ditch

Grass and eeds 3 *

. I ------'= 6 5 Water

* Nest C:Ji Trees - ·-·-·- Fence ====Dirt Road

Figure 4. Map of Tract II Scale: 1 11 = 200' = 1 grid 8

Briefly, the climate of Payne and Noble counties is temperate in nature, with a mean annual temperature range of 60.33°F and a mean annual precipitation of 34.31 in. The soils that comprise the area are largely composed of Permian clays and shales that have weathered to form fine soils well suited to the growth of grasses which dominate the region. The area has been generally described as the "Redbeds Plains" area by Bruner (1931). The vegetation comprising the area has been described as a Stipa - Koeleria association by Bruner (1931).

TABLE I

OOMPARISON OF PHYSICAL CHARACTERISTICS OF THE STUDY TRACTS

Item Tract I Tract II

Size 45 acres 23 acres Shape square rectangular

Elevation above 923-965 feet 921 feet sea level Land use grazed cleared for impoundment Topography fiat to gently gentle slope rolling 9

Vegetation of the Study Tracts

Tables II and III present the most commonly observed plant species found on the two study tracts, their observed uses by Dickcissels, and their relative abundance. Generally, it can be noted that the species found on Tract II are characteristically plants that are

"weedy" in appearance and perhaps represent species characteristic of areas in early secondary succession. Most plant species that occurred were used for song posts, but it was difficult to ascertain if these plants provided direct sustenance to the . Since the scope of this study was necessarily limited, feeding observations plus fecal and stomach analyses were not lilcluded.

TABLE II

COMMONLY OCCURRING FLA.NT SPECIES FDUND ON TRACT I

Relative Plant Species Observed Use Abundance

Sand plum (Prunus angustifola) Song post Occasional Honey Locust (Gleditsia triacanthos) Song post Occasional Pecan (Carya illinoensis Song post Frequent American Elm (Ulmus americana) Song post Frequent Mexican Plum (Prunus mexicana) Song post Frequent Wild Rye (Elymus canadensis) Food Abundant Japanese Brome (Bromus japonicus) Food Very Abundant Torrey Nightshade (Solanum torre}) Encircled nest Occasional Johnson Grass (Sorghum halepense Nestlilg Frequent Material lC

TABLE III COMMONLY OCCURRING PLANT SPECIES FOUND ON TRACT II

Relative Plant Species Observed Use Abundance

Annual Sunflower (Helianthus annuus) Song post Occasional Sand Plillil (Prunus angustifola) Song post Rare Cultivated Peach (Prunus persica) Song post Rare Curlycup Gillil Weed ( Grindelia sguarrosa) Attracts Very insects abundant Johnson Grass (Sorghum halepense) Nesting Frequent material White Sweet Clover (Melitotus alba) Attracts Frequent insects Japanese Brome (Bromus japonicus) Food Abundant Sowthistle (Honchus arvensis) Support for Very nests 2, abundant 4, 5, 6 Horse Weed (Conyza canadensis) Support for Very nests 2, 3 abundant

Various vertegrates were encountered on both study tracts. A complete listings of species and their scientific names is cited in Table IV. The various vertegrate species present on Tract I are believed to be typical for tall grass prairie habitat. Difference between the two tracts may reflect the disturbed nature of Tract II. Of the birds observed on both tracts, the Eastern is probably the most significant numerically, especially since it may occupy the same general niche as the Dickcissel. Also, the presence of the Red-winged Blackbird on both tracts might be a reflection of the presence of wet and swampy areas. TABLE IV ANIMALS OBSERVED ON STUDY TRACTS

Species Observation Tract I Tract II Relative Abundance - Dogs (Canis familiaris) Tracks x x Occasional Cottontail Rabbit (Sylvilagus floridanus) Sighted x: x Occasional Coyotes (Canis latrans) Heard call x Occasional Skunks (Mephitis memphitis) Odor x x Frequent Raccoons (Procyon lotor) Tracks x Frequent White-footed Mice (Peromyscus leucopus) Sighted x x Frequent Cotton Rats (Sigmodon hispidus) Sighted x Occasional ( magna) Sighted x x Abundant (Sturnella neglecta) Sighted x Abundant Red-winged Blackbird (Agelaius phoeniceus) Sighted x x Frequent Scissor-tailed Flycatcher (Muscivora forfic) Sighted x x Frequent Red-tailed Hawk (Buteo jamaicensis) Sighted x x Occasional Mourning Dove (Zenaidura macroura) Sighted x Abundant Bobwhite Quail (Colinus.virginianus~ Heard call x Frequent Common Night Hawk (Chordeiles minor Sighted x Frequent ( cyan)a) Sighted x Occasional Killdeer (Charadrius vociferus Sighted x Frequent Sparrow Hawk (Falco sparverius) Sighted x Rare White-rumped Sandpiper (Erolia fuscicollis) Sighted x Occasional Mallard (~ platyrhynchos) Sighted x Occasional Barn Swallow (Hirundo rustica) Sighted x Frequent

I-' I-' 12

The Western Meadowlark, the Mourning Dove, and the Dickcissel all seemed to occur in the same habitat in Tract I. However, from all observations made, there seemed to be no inter-specific aggression or competition among these bird species. Possible predators were ob­ served, but no specific predation was noted with the exception of a loss of all 5 eggs from nest 3, Tract II. No evidence of the of predator was found.

I made no attempt to make a complete census of birds other than the Dickcissel. On the basis of 3 weekly counts, I have estimated the Dickcissel population as being 20 breeding pairs on Tract I and 15 breeding pairs on Tract II. A computation of breeding pairs on each tract indicates an average of 2.2 and 1.7 breeding pairs per acre on

Tracts I and II respectively. An analysis of these figures indicates a 23 per cent difference in population density. CHAPTER III

MATERIALS AND METHODS

The collection of nesting data was accomplished by direct personal observation aided by a pair of 7x50 binoculars. Field notes were re­ corded on 3"x5" index cards.

Observations were made by sitting quietly near the birds or nests.

It took a few visits to each nest to determine the best vantage point from which to observe the activity in the area around the nests. Some of the birds exhibited more tolerance toward the observer than others and as a result, I found it necessary to adjust the distance of obser­ vation. I found no indication that the observations taken through such a trial and error approach altered the behavior of the birds.

Temperature, wind, and cloud cover were recorded at the beginning and end of each observation period and at any time that the conditions

changed noticeably. Temperature was determined by means of a Fahren­ heit thermometer, held two feet above the open ground in the shade.

Wind condition was categorized as slight, moderate, gusty, or strong;

cloud cover was recorded as clear, partly cloudy, overcast, or rain.

These data were recorded with the objective that I might be able to

draw conclusions concerning behavioral patterns with relation to weather fluctuations. However, I was unable to draw any correlations between weather conditions and behavior.

Measurement of linear distances of tract sizes were determined

13 14 by a steel tape. Nest dimensions were measured by a centimeter rule.

All measurements were made to determine parallels between the findings of this study and previous studies cited in the literature. Measure­ ments of nest dimensions taken in this study correspond with those examined by Overmire (1962) and Crabb (1923) in their studies.

Color photographs were taken with a Polaroid Colopack II, a Kodak

World's Fair Flash camera, and a Marniya/Sekor 35 mm. camera. Pictures were taken of the nests and the habitat around the nests for the pur­ pose of documentation.

Field work was carried on from May 17, 1971 to June 13, 1971.

Censuses were taken weekly to determine the density of breeding pairs of Dickcissels on the study tracts so that comparisons of tract densities could be made. The census technique used was that described by Pough (1947). With this technique, the assumption is made that each singing male, resident on an established territory, indicates the presence of a breeding pair. A search for nests was made in the areas where Dickcissels were repeatedly found. Notes concerning the ecology of the area and nest data (when nests were found) were recorded during each observation period. These results are recorded in Chapters

I and II. CHAPTER IV

NESTS

The bulk of the Payne County population of Dickcissels arrive in late April or early May. Baumgartner and Howell (194S) reported the

Dickcissel to be an abundant summer resident, seen from April 25 until

September 12. Sutton (1967) reported the Dickcissel as being seen in

Oklahoma from April lS, to November 7. Since the observations made for this study began 17 May, no attempt was made to determine the earliest arrivals in the area.

Courtship begins soon after arrival and nesting is underway by the latter part of May (Sutton, 1967). May 26 is the earliest reported date for a spring nest found in Oklahoma. This nest, located near

Minco, Oklahoma, contained one egg (Wetmore, 191S). I found two nests on May 27, 1971. One nest was located on Tract I and contained 1 nestling and 4 eggs. The other nest, found on Tract II, contained 5 nestlings. Crabb (1923) reported the incubation period of Dickcissel eggs to be 10 to 11 days. Considering the average incubation period to be 10 to 11 days, the nest found on May 27 on Tract II could have been completed as early as May 11. According to all available litera­ ture, this data represents the earliest recorded date for nest initiation and thus establishes a new record for the initiation of nest building in north central Oklahoma.

15 16

Nest Construction

I did not observe any nest construction activity by Dickcissels. However, Gross (1921) gives the average time for construction of the Dickcissel nest to be four days. He also provided the following description of the nest:

Dickcissel nests are bulky and somewhat crude in general appearance, but are substantial structures. They vary little in size and shape; the average measurements of ten typical nests are as follows: outside diameter 12.2 cm., inside diameter 6 cm. by 6.8 cm., outside depth 6.3 cm., inside depth 4.6 cm. The materials used seem to be those near at hand and vary according to the immediate surroundings. The exterior of the nest is usually com­ posed of coarse weed and grass stems, or cornstalk fibers interwoven with a few leaves and grasses; the interior is lined with finer grasses, rootlets, or hair. Some nests may be made up almost entirely of one type of grass, including the lining. Though most nests are firm and well made, those built well above the ground are often so insecurely attached to their support that the least disturbance may dislodge them.

Two of the Dickcissel nests on Tract II were somewhat elevated.

Nest 5 was 15" from the ground and nest 6 was 2211 from ground level. Both of these nests were poorly attached to supporting vegetation.

I found it necessary to adjust nest 6 as it was tipped at such an angle as to endanger the eggs. I found that this problem did not present itself with nests built close to the ground. Specific infer- mation concerning nest dimensions is given in Table V. Included in Table VI is a list of the 6 Dickcissel nests that were found on the study tracts, the number assigned to each nest, the date the nest was found, status and location of study tract. The location of each of the nests is plotted in Figures 3 and 4. 17

TABLE V DIMENSIONS OF SIX DICKCISSEL NESTS FOUND ON STUDY TRACTS

Ext. Diam. Int. Diam. Ext. Depth Int. Depth Nest # (mm) (mm) (mm) (mm)

1 85 68 43 40 2 90 73 70 60 3 80 62 50 46 4 115 78 63 51 5 105 67 80 71 6 110 61 _§1_ ....£_ TOTAL 585 409 389 320 RANGE 80-115 78-61 83-43 71-40 MEAN 97 .5 68.2 64.8 53.3

TABLE VI NUMBER, DATE FOUND, STATUS AND LOCATION OF SIX DICKCISSEL NESTS FOUND ON STUDY TRACTS

Nest # Date Found Status Location

1 Z1 May 4 eggs, 1 nestling Tract I 2 27 May 5 nestlings Tract II 3 28 May 1 egg Tract II 4 1 June 1 egg, 4 nestlings Tract II 5 12 June 4 nestlings Tract II 6* 12 June 5 eggs Tract II

*Dr. Barclay found this 25 May, half completed. 18

Overmire (1962) located 94 Dickcissel nests near Stillwater, of which only 25 percent were on the ground. Gross (1921) and

Stockard (1905) found the Dickcissel to be primarily a ground nesting

species, and have further concluded that the males take no part in nest construction. Of the 6 nests found during my study, only the

single nest on Tract I was built on the ground. The five nests located on Tract II ranged from 3 cm. to 59.9 cm. abbve the ground. CHAPTER V

CLUTCH COMPLETION

Observations of the time of egg laying indicated that the eggs were laid at one day intervals. The exact time of egg laying was not determined. The clutch size in all nests was 5 eggs each. One nest had only 4 nestlings and one unhatched egg when found. Crabb (1923), reported a mean clutch size of 5 eggs laid at one day intervals.

Stockard (1905), found that with 14 nests, 11 sets had 5 eggs and 3 sets had 4 eggs. Lack (194e), stated that average clutch-size is characteristic for each and each family of birds in the same

region. Figure 5 shows nest number 3 with completed clutch. Crabb (1923), observed that incubation began when the penultimatE egg was laid. Nest 3 on Tract II was the only nest that I found in which the female was still completing her clutch. I did not observe the female on this nest at anytime before the clutch was completed.

The clutch was completed 1 June. The eggs were gone from the nest on 10 June. I suspect that either a raccoon or a snake was responsibJ

for robbing the nest.

19 Figure 5. Nest 3 with Completed Clutch CHAPTER VI

ADULT PREFLEDGING ACTIVITY

As with the construction of the nest and incubation of the eggs,

care of the nestlings was an activity solely of the female. At no

·time did I observe any male taking direct part in the care of the

young. Gross (19ZL) observed a sparrow hawk capture a female Dick­

cissel in plain view of the male. The male continued singing on his

song posts for 2 or 3 days while the nestlings slowly starved.

Of the 6 nests found, 4 had nestlings in them when discovered.

The behavior of the female toward the nestlings was similar in all

cases. The following is a field record of adult female prefledging

activity observed at the nest site on Tract I 30 May from 12:30 p.m.

until 3:30 p.m. This record typifies the observed female behavior.

The nest contained 2 nestlings and 3 eggs. Table VII represents

typical female food gathering behavior observed during the course of

this study.

On 30 May, 1971, I flushed the female from the nest at 12:47,

recording both the male's and the female's actions until I left the

area at 3:30 p.m. During this time the female made 7 trips away from

the nest, returning each time with what appeared to be food. On

trips 1 and 3, the male accompanied her to the nest area. The rest of the time, he spent singing from song posts.

21 22

TABLE VII

TYPICAL FEEDING TIME TABLE OF DICKCISSEL

Returned to Minutes Away Entered Trip # Left Nest Nest Area From Nest Nest

1 12:47 12: 50 16 1:03 2 1:12 1:19 9 1: 21 3 2:15 3 2:18 4 2:19 2:23 6 2: 25 5 2:43 4 2:47 6 2:48 2:51 5 2:53 7 3:03 3:07 7 3:10

I observed an identical pattern of behavior on subsequent ob-

servations of the nest on Tract I. I found, however, that I could

approach more closely to the nest before the female would leave and go into her characteristic "broken wing" display. I eventually could walk to the nest and observe the female sitting on the nest for a few

seconds before she performed her injured act. Her increased tolerance

for my presence may be an example of habituation (Welty, 1962).

Fledging took place, with nest number 1, on 3 June. Thus the

time between hatching and fledgingwas 8 to 10 days. Gross (1921) also reported that the Dickcissel leaves the nest 8 to 10 days after

hatching. The nest at Tract I was the only nest for which I have a

complete record of the time between hatching and fledging. Figure

6 shows the nest at Tract I with the first nestling in it. 23

Figure 6. Nest at Tract I with First Nestling

I found 4 nests with nestlings, one on Tract I and 3 on Tract II.

In all cases , all the young birds in a given nest fledged on the same day. Once the birds had fledged, I was unable to locate any of them.

Gross (1921) , reports that the fledged Dickcissel acquires the ability to fly within 2 or 3 days , and at 10 to 11 days the young bird may fly up to 150 feet .

All of the nestlings found in the a:iurse of my study fledged.

I have no data on the survival of the fledglings . Data on hatching and fledging success of the 6 Dickcissel nests are included in

Table VIII. 24

TABLE VIII

HA.TCHING AND FLEDGING SUCCESS OF 6 DICKCISSEL NESTS

Eggs Eggs Percent Number Percent Tract Nest # Laid Hatched Hatched Fledged Fledged

I 1 5 2 40 2 100 II 2 5 5 100 5 100 II 3 5 0 0 0 0 II 4 5 4 so 4 100 II 5 5 4 100 4 100 II 6 2 _Q_ 0 0 0 Totals 30 15 41 15 100

In order to determine the degree of success two calculations were made:

1. Hatching success no. of eggs hatches = x 100 no. of eggs laid

2. Fledging success = no. of eggs hatched x 100 no. of young fledged CHAPTER VII

CONCLUSIONS

Observations of the nesting activities of Dickcissels on two study tracts, 23 acres and 45 acres in size, in north central Oklahoma were made during the time period 17 May to 13 June, 1971. The purpose of the study was to add to the understanding of the nesting biology of the bird in the region.

The conclusions drawn from this study are as follows:

1. Sutton (1967) indicated that nesting is underway by the latter part of May. The earliest date recorded for a completed nest prior to my study was 26 May (Wetmore, 1918). I found a nest which was com­ pleted approximately 11 May, 1971. These data represent the earliest

recorded date for nest initiation and thus establishes a new record

for the initiation of nest building in north central Oklahoma.

2. The role of the sexes in parental care conformed with that recorded in other studies. The males observed in the present study did not participate in the care of the young.

3. The fledging success of the Dickcissels observed was lOO}b. Nice (1957) indicated that, among , the percentage of young that are fledged is typically around 6Cfl/o. The sample size in this study is insufficient to make a positive correlation.

4. An analysis of census data indicates a 23 percent difference

in population density between the two tracts. However, further study

25 would be necessary in order to form a valid conclusion as to habitat preference in relation to the two study tracts.

5. A study by Gross (1921), Overmire (1962), and this present study indicates that the Dickcissel may have an important economic status and further work on the life history of this bird is therefore warranted. LITERATURE CITED

Baumgartner, F. M. and J. c. Howell. 1948. The numerical and seasonal statuses of the birds of Payne County, Oklahoma. Oklahoma Acad. Sci. Proc. 27: 45-59· Bruner, w. E. 1931. The Vegetation of Oklahoma. Ecol. Monogr. 1: 99-188. Crabb, E. D. 1923. Notes on the nesting of a pair of Dickcissels. Auk 40: 606-609. Gross, A. O. 1921. The Dickcissel (Spiza americana) of the Illinois Prairies. Auk 38: 1 - 26, 163-184. Lack, D. 1948. The significance of clutch-size. Ibis 90: 25-45. Nice, M. M. 1957. Nesting succession in altricial birds. Auk 74 (3): 305-321. Overmire, T. G. 1962. The effects of grazing upon habitat utiliza­ tion of the Dickcissel (Spiza americana) and Bell's Vireo (Vireo bellii) in North Central Oklahoma. Ph.D. Thesis. Okla. State Univ., Stillwater (unpublished). Peterson, R. T. 1947. A field guide to the birds. Houghton Mifflin Company, Boston. 290 PP• Pough, R. 1947. How to take a bird census. Mag. 49: 288-297. Stockard, c. R. 1905. Nesting habits of birds in Mississippi. Auk 22:146-158, 273-288. Sutton, G. M. 1967. Oklahoma Birds. Univ. of Okla. Press, Norman. 674 PP• Welty, J. C. 1962. The life of birds. w. B. Saunders Co., Philadelphia. 546 PP• Wetmore, A. 1918. Birds observed near Minco, Central Oklahoma. Wilson Bull. 30:2-10, 56-61.

27 VITA Gordon Alan Berry Candidate for the Degree of Master of Science

Report: THE NESTING BIOLOGY OF THE DICKCISSEL (SPIZA AMERICANA) IN NORTH CENTRAL OKLAHOMA Major Field: Natural Science Biographical:

Personal Data: Born in Dover, New Hampshire, January 7, 1936, the son of Mr. and Mrs. Wyatt B. Berry. Education: Graduated from Dover High School, Dover, New Hamp­ shire; received the Bachelor of Education degree from Keene State College at Keene, New Hampshire in 1961; completed requirements for the Master of Science degree in July, 1971. Professional Experience: Science teacher, Somersworth Junior High School, Somersworth, New Hampshire, 1961 to 1965; Biology and chemistry teacher, Berwick High School, Berwick, , 1965 to 1966; Science teacher, Alverne Junior High School, Hudson, New Hampshire, 1966 to 1967; Biology teacher, Exeter High School, Exeter, New Hamp­ shire 1967 to 1970. Name: Gordon Alan Berry Date of Degree: July 30' 1971 Institution: Oklahoma State University Location: Stillwater, Oklahoma Title of Study: THE NESTING BIOLOGY OF THE DICKCISSEL (SPIZA AMERICANA) IN NORTH CENTRAL OKLAHOMA Pages in Study: 27 Candidate for Degree of Master of Science Major Field: Natural Science Scope and Method of Study: The nesting biology of the Dickcissel was studied from 17 May to 13 June, 1971, on a 45 acre tract in Payne County and a 23 acre tract in Noble County. All field data were collected by personal observation of the activity associated with 6 nests. Nest construction, incubation, and prefledging activity and behavior of adult Dickcissels were included. Findings and Conclusions: There was no evidence that Dickcissels were paired on arrival •••• i.e. pairing apparently occurred after arrival. Only the females were involved in nest con­ struction, incubation, and care of the prefledglings. Eggs were laid on successive days. Although eggs of the same nest did not usually hatch on the same day, the young of the same nest did fledge on the same day. The hatching success of 30 eggs in 6 nests was 41% and the fledging success was 100%. The earliest recorded date for nest initiation by the Dick­ cissel. in north central Oklahoma was established during the course of this study.

ADVISER'S APPROVAL --?"!"'fl\...... ~~-· -----1 __, _..iL.__.._ .....xx_____...... ·~--"--· ~--~----